I don't think Ren'Py allows for this, unfortunately (or if would take a professional coder). Besides lackslyricism' tips (especially savescumming), I'll also point out:
- scrolling back/up with the mouse will let you go back quite far, often multiple choices back
- Skip mode (via the menu, or with the Tab button for me) makes it faster to zoom through previously-played sections again if you do need to restart or pick up from an old save. Especially useful with the "Seen text" setting from the options menu - this will make the game stop skipping when encountering text you haven't previously seen, which helps in confirming that you've unlocked a new thing.
- Doing a few casual playthroughs in story mode just to complete a few routes and get the New Game + stat bonuses helps a lot for cases where you keep cutting it just too close (esp helpful for things like getting best dialogue options from multiple characters at the welcome feast, like the critical last few Courage points to accept Zarad's invitations, extra Intelligence to help nailing Lyon's first date, or a little Manipulation to help out the backgrounds that can't get much from character creation)
Aside from that, yeah, you just gotta accept that it's very much a Game Played With Spreadsheets if you're going for perfection (especially if you're playing Challenge mode with no NG+). Personally I love that!, but unfortunately it's not everyone's thing.