Hello everyone. I am attempting to capture mirrored VGA output from a slot-loading iMac. Specifically VGA, SVGA, and XGA with some unusual refresh rates.

I have a crap solution in place but the quality is unacceptable. That involves and old GV-USB2 I have in concert with an iTViewMac custom VGA to S-Video converter I still have from back in the day, made and sold just for this version of iMac. But the resolution is really only acceptable for VGA 640x480 and still blurry and yuck.
Meanwhile I have an Avermedia LiverGamer HD in another PC for high-quality HDMI game capture. So, hey, I thought, I just need to get this VGA output into HDMI. Oh hey look there's a cheap adaptor on Amazon. So began the adventure. Obviously the cheap adaptors weren't worth the money: unable to handle the refresh, splitting out various colors and wrong in tint overall, though at least surprisingly stable and clear and 1x1 pixel perfect with black border within the HDMI image my TV shows me... that my capture card complains is an unsupported resolution.
Thus I am here with a fresh account and whiny tone looking at OSSC, intimidated but hopeful, unable to find a resource that can tell me if those weird hertz up there would be acceptable input resolutions for an OSSC, using the apparent input VGA port. And I'm thinking, "Really? I bought a custom cables for PS2, classic XBox, Gamecube... separately. Now I'm gonna buy an OSSC?!? Because of the iMac?!"
Trying to find a way out of it with a simpler plug-and-play thing, I found this thing:
https://muxlab.com/pro-digital/vga-to-hdmi-co … ter-with-scaler

https://www.bhphotovideo.com/c/product/112596 … er.html/reviews
This might be a great solution for others in similar shoes as mine but with a more reasonable machine instead of this crazy high frame rate iMac. But I looked up supported resolutions and we're not getting anywhere near an 800x600 @ 95Hz: https://muxlab.com/wp-content/uploads/2015/02/500149-IG.pdf much less the 640x480 @ 117Hz. Also, about the same price as an OSSC.
Oh and hey in checking for my options as to whether I could force that iMac to show some lower refresh rates, I was amused to find a 2004 thread exactly answering my question: https://macosx.com/threads/imac-g3-screen-resolution.41194/
So... I am at the edge of the OSSC abyss. I'll jump off... return or sell those custom cables I bought and learn all about this thing... if I can get one specific question answered:
Will an OSSC be able to handle those input resolutions and refresh rates listed, and output a pixel perfect result within an 1080p HDMI output that my capture card will accept?
Thanks in advance for helping an old man, who is new to the forum.