I do like the ability for non-casters (and casters who don't have that spell on their spell list) to be able to read scrolls, but it definitely should be a difficult skill check. There's no "Use Magic Device" in 5e, so maybe an Arcana check with DC = 15 + spell level? A failure results in the loss of the scroll.
A 12-Int, level-5 fighter with proficiency in Arcana would then have a ~45% chance to successfully cast a 1st-level spell, which seems fair. Limiting enough that you wouldn't regularly do it, but in certain scenarios taking the risk might be worth it. A rogue with arcana expertise would have an even better chance, which allows them to benefit more from their skill-monkey role.
Another homebrew suggestion which sucks.
This is like 6 posts old in the specific conversation chain, but alright. Do you not like the concept of UMD at all, or do you think that it only made sense in previous D&D editions but not in 5e ('s lore, classes, magic system)?
This question is also to you @1varangian.
Following on what you were saying - I understand the scrolls themselves are written in Draconic, Celestial, Netherese and Demonic - its not just a recipe written in common like making chicken soup. If you don't pronounce that shit right you may catch fire, explode, or be polymorphed into a slug - like rolling on the Wild Magic table but only negative outcomes.
Scrolls are "written in a mystical cipher," which may be Draconic+etc, sure. And I agree that it's dangerous if you get it wrong, but it's possible you get it right. The more familiar you are with mystical ciphers (arcana) and languages (intelligence), the higher chances of being able to pronounce it correctly.
So would you want a penalty (roll on a negative-only WM table) if you fail the arcana check to use a scroll? Or for simplicity, if the spell is harmful just have it go off in your face and if it's a buff spell (Bess), make it a negative effect (Bane).
