At least once or twice in every run?
I don't think it really matters because it's a single player game at the end of the day, and even with challenges the ranking doesn't really mean anything... and tournament have rules so you have to play by that.
This topic came up a while back in the StS Discord and people got weirdly tied up and aggravated in how it's the "wrong" way to play and one should never restart combats. Again, for god's sake, it's a single player video game.
I personally see no issue with it, whether it's me or someone else opting to do it. It's not like you're using a cheat engine to predict enemy movements in a competitive game where game ranking that can translate to monetary value.
I can recommend Krumit's Tale. Though it is on mobile and not quite the depth and longevity as StS and Monster Train, I found it scratching the same itch for me. Creative deck building with many different possibilities and combinations of cards. From what I played so far is feels very balanced and replayable (I have not 100%-ed it yet but cleared multiple "ascensions" on all characters).
https://play.google.com/store/apps/details?id=com.slothwerks.krumit
Download and install Everything from here: https://ninite.com/everything/
It can search your entire PC for files within a few seconds. Search for the file metagameSave.json. Wherever it shows up on your old PC, you want to copy that entire folder to your new one.
I'm not very familiar with gamepass, it's on PC, right?
If so, all you would likely need to do is to move the metagameSave.json file from wherever gamepass saves it to this location: C:\Users\<profilename>\AppData\LocalLow\Shiny Shoe\MonsterTrain
I recommend using a search program like Everything to find out where the metagameSave.json file is currently located. There should be only one of them on your PC.