Ok, given that I have a lumbar/cervical spine essentially devoid of functional discs, lumbar stenosis recently fixed, cervical stenosis getting worse by the month, I have you by about a decade on age, and I used to be significantly nearsighted/astigmatic prior to cataract surgery - I can sympathize and hopefully help with your eyebox issue.
There is one very significant difference that will complicate your adjustments: prescription glasses, especially if they are thin-profile progressives with their tiny "sweet spot" in the middle of the lens. You might want to consult with a sports glasses company. Decot was my go-to when I needed progressives, but their glasses are more oriented to clay target sports... I wear Rudy Project shooting glasses now, and I honesty don't know if their customer service can/will step up like Decot did. I took up rifle after cataract surgery; it's for sure that daily-wear thin-profile progressives were totally unsuitable for clay target / shotgun disciplines and I doubt that they'd be much better for rifle. If you're trying to use daily-wear prescription glasses, especially thin-line ones, that may be the cause of your scope eyebox issues right there.
With all that said:
First, get off your belly. Use a bench. If the range where you shoot doesn't have benches, buy or build a folding one and buy a cheap drummer's stool to sit on. You want to be sitting quite upright. Save the prone mess for when you have to use it, and, when you do, start with bipod set up high and support your chest on a backpack or pillow bag (big poofy support bag) so your back bends in the thorax and you don't have to hyperextend your neck. You'll probably find that prone positioning gets easier with practice. I can get into a lower prone position now than when I started, but I only do prone when I have to. Old guys spell prone "b-e-n-c-h."
Second, set up your rifle so you have a steady cheek weld with your head up, reducing strain on your cervical spine. I know when I'm hyper-extending my neck because i get pain radiating down my arms.
@badgerfan is correct in his approach involving rifle setup with the shooter's eyes closed. Honestly, I've been shooting so long (60+ years, with about half of that in competition) that I just fall into a solid mount with about any rifle or shotgun I pick up.... you're gonna have to practice. You should be able to set your rifle on a bench, supported by its bipod, sit down behind it, close your eyes, mount the rifle, and open your eyes... and you should be very close to or perfectly positioned in the scope's eyebox
at any magnification. Again, daily-wear prescription glasses are likely to complicate this.
You don't mention what kind of stock or chassis you have on your rifle. If it doesn't have an adjustable cheekpiece (comb), you're extremely disadvantaged.
Assuming you do have an adjustable comb, you need to work on adjustments to keep your head up with as little neck extension as possible. You're likely to run into the totally, utterly antiquated opinion that your scope needs to be mounted as close to the barrel as possible. This is outdated nonsense. You want to be comfortable, and with neck issues "comfortable" means no scrunching your head pushed way forward and hyperextending your neck.
I urge you to seek knowledgeable written and in-person assistance before you throw more money at different scopes/rings. As has been written, the Razor 4.5-27x56 is a pretty forgiving scope... I have two of them, and their eyeboxes are as good as the far more expensive ZCO I also own.
Good luck.
