Quote Video originally captured 25 years ago on Video8 and Hi8 analog tape. I digitized this video
several years ago and the resolution is now 720x480.

See this tutorial: https://youtu.be/YczLRshnxQ8 . If you intend to save the old interlaced video to a modern progressive video format then you need to decide on whether you want to change it or keep it in the old interlaced mpeg-2 format.

You did not specify how you captured the video. See this recent thread for reccommendations for better quality: https://forum.cyberlink.com/forum/posts/list/83811.page .

If you have captured to MPEG2 already, and no longer have the original tapes, you have crippled, to some degree, your best ability to repair-restore the video. Using a good VCR with S-video is greatly preferred, and if it has a built-in line TBC it's even better.
Consumer analog video is best captured using a lossless AVI codec, interlaced, and a 4:2:2 color YUV space, at 720x480.
Because PD cannot do that I use a third-party freeware to capture and avoid an entire round of heavy MPEG compression.
However, you have what you have and we need to work with that and live with the second round of video compression.
In addition to the in-house PD filters, New Blue and Boris have decent filters to minimize grain, sharpen, and of course fix colors, white balance and stabilize, and cuts.
Each will be working on an already compressed video so you might consider less-is-more approach.
In the end, do not expand the video to avoid the overscan (on the bottom), and nasty edges, that will simply degrade the image even more. Use a mask to tweak the edges, be sure to keep the mask centered.
If any tapes have video content flagging or bending at the top of the image, you have 3 choices, mask it, which loses a big portion of the video, expand it out of the frame, also losing image quality, or leave it.
The only way to remove the flagging is to recapture using a Panasonic ES-10, or 15 (some say the ES-20 also has some of this ability but don't bank on it) as a pass-through pseudo Time Base Corrector that magically removes that flagging. You'll need the Panny remote to shut off noise reduction as it is too strong.
If you recapture in PD, bump up the bit rate from 8000 to 12000 to minimize compression artifacts, but it's still not as good as lossless capture using VirtualDub 1.911 and Huffyuv codec. HP Envy Phoenix/4thGen i7-4770(4@3.4GHz~turbo>3.9)
Nvidia GTX 960(4GB)/16GB DDR3/
Canon Vixia HV30/HF-M40/HF-M41/HF-G20/Olympus E-PL5.
Tape capture using 6 VCR, TBC-1000, Elite BVP4+, Sony D8 camcorder with TBC.
https://www.facebook.com/BarryAFTT

BarryTheCrab explained very well with dealing with VHS videos.
I used a Philips recorder to capture VHS tape, then in PD I used SVRT to avoid deteriorating the image.
But recently I think PD improved its MPEG 2 and I started to zoom the image to remove the defective edges.
This dealing with VHS to DVD (interlaced)
Recently I was asked to extract part of a DVD (vhs copy) to record on the MP4 pen drive.
I did some tests, I thought it was best to save at 60fps progressive, this makes the video roll smoothly without the shaking that happens with 30 fps for the same case. XEON-E5-2680 v4 / Mem. 16GB DDR4
M.2 NVME 512Gb / 2-SSD Sata3 1TB
AMD RX570 / Display Philips 272V8
Windows 11_64Pro / PD22/365

I also deinterlace using QTGMC to 60p. Then I mask and edit, do color etc in PD.
PowerDirector is actually last in line for my workflow. But yes, even within PD use a delivery of 60p. HP Envy Phoenix/4thGen i7-4770(4@3.4GHz~turbo>3.9)
Nvidia GTX 960(4GB)/16GB DDR3/
Canon Vixia HV30/HF-M40/HF-M41/HF-G20/Olympus E-PL5.
Tape capture using 6 VCR, TBC-1000, Elite BVP4+, Sony D8 camcorder with TBC.
https://www.facebook.com/BarryAFTT

Quote

See this tutorial: https://youtu.be/YczLRshnxQ8 . If you intend to save the old interlaced video to a modern progressive video format then you need to decide on whether you want to change it or keep it in the old interlaced mpeg-2 format.

You did not specify how you captured the video. See this recent thread for reccommendations for better quality: https://forum.cyberlink.com/forum/posts/list/83811.page .

UPDATE:

I CAPTURED ORIGINAL VIDEO ON A SONY CCD-FX510 NTSC8 20 - 28 YEARS AGO.
THE MEDIA I USED IS LABELLED "VIDEO8" OR SIMPLY "8", SOME ARE DESIGNATED "MP".

Quote UPDATE:
I CAPTURED ORIGINAL VIDEO ON A SONY CCD-FX510 NTSC8 20 - 28 YEARS AGO.
THE MEDIA I USED IS LABELLED "VIDEO8" OR SIMPLY "8", SOME ARE DESIGNATED "MP".

So if they are Video8, or even Hi8, the same rules apply as for VHS. If originally captured to any compressed format the end result of any editing other than cuts, will be slightly degraded video as you will need to re-render making it a second generation compression copy.
The important thing is you HAVE the VIDEO which is priceless, even if imperfect. I just mention these other facts as a lesson to others.

AVplayvideo...you mention that you suspect that CL has recently improved their mpeg2 output.
When do you believe this happened and is it based on your observations?
If the codec has been improved I might consider getting 19. I had 18-365 but now use 17. HP Envy Phoenix/4thGen i7-4770(4@3.4GHz~turbo>3.9)
Nvidia GTX 960(4GB)/16GB DDR3/
Canon Vixia HV30/HF-M40/HF-M41/HF-G20/Olympus E-PL5.
Tape capture using 6 VCR, TBC-1000, Elite BVP4+, Sony D8 camcorder with TBC.
https://www.facebook.com/BarryAFTT

Quote AVplayvideo...you mention that you suspect that CL has recently improved their mpeg2 output.
When do you believe this happened and is it based on your observations?
If the codec has been improved I might consider getting 19. I had 18-365 but now use 17.

This happened in a PD18 / 365 update
In PD19 / 365 I use it now continues.
I remember it was impossible to render MPEG2 the result was terrible, from this update I started to zoom in the image to remove the garbage bars of the captured MPEG2 from the VHS
There is still loss, much less than before the biggest deterioration is due to the zoom.
I think it's also better for converting FullHD to MPEG2.
I recommend taking the trial version to make sure of this before buying.
On the other hand, version19 brings other improvements XEON-E5-2680 v4 / Mem. 16GB DDR4
M.2 NVME 512Gb / 2-SSD Sata3 1TB
AMD RX570 / Display Philips 272V8
Windows 11_64Pro / PD22/365