TotK is better in every way but BotW is once in a lifetime experience due to how contemplative it can be. You’re not going to play both at the same time and they benefit from playing in order. If you’re low on cash buy some used copy of BotW off someone on Vinted* and sell on Vinted once done, then do TotK.
* or Craiglist or OLX or whatever is used locally where you live