This is very expensive in fees right now and if you have a watch only wallet created from a single public address then the change can only be sent back to that address. So it seems crazy to pay for 40 input uxtos rather than just 1.
Is that correct ?
Yeah! It's just because the same address gets alot of inputs the only way to avoid this if you care about your primacy is
Inputs consolidation: you spend all your inputs in a single transaction when the fee is quite low to a new adresss
You can check
https://bitcointalk.org/index.php?topic=2848987I haven't used Bitcoin core for any transaction because I couldn't meet up with the sync process so I cannot really answer if Bitcoin core does that but as have said earlier,
Generally, every transaction in bitcoin spends all inputs same experience with Sparrow so I think Bitcoin core will also do same
You can check
https://learnmeabitcoin.com/beginners/guide/transactions/