there is a disadvantage to consolidating all your addresses/inputs/whatevers. and that is say you have 10 btc spread in 20 or 30 addresses. maybe the most in one addy is 0.35 btc. if you send btc to someone from that addy thats all they see you have.. that 0.35 btc. if all had been consolidated that person now would know you have 10 btc.
i prefer a lot of various sized utxos to select from so that i can send just enough, and not give away how much coin i may have.
ill accept the extra cost.
edit: probably got some terminology wrong, feel free to correct please.
With my limited knowledge on consolidation, privacy, fee and mixing I think consolidation can be used to save your fee by reduce the size of transaction from 10 inputs to 1 output. You consolidate and prepare 1 output for later spending.
Consolidation is applied when fee is low and I don't feel reasons to consolidate if fee is not cheapest (1 satoshi per byte).
Privacy it is nonsense to consolidate all your inputs into 1 outputs if you don't plan to spend all of your bitcoin with a single transaction. Consolidate 10 inputs to have 10
BTC and at the end spend out only 0.35
BTC and the rest 0.65
BTC will be left in your wallet with a new change address. I don't it is a thing to do.
Consolidate and mixing are different but they have a common point. Consolidate or combine mixed coins can reduce your anonymity.
If I have 10
BTC, saving $5 dollar is not my big interest. I will make a few transactions if I want to keep up my anonymity.
That person made a transaction from 753 inputs (ignore how the person used terrible fee).
https://blockstream.info/tx/3ba0c9eaf3185898164518cda7e3433d1d2049188d737f2b2a7e188aaeb8b4de