You can do 2 things - install a custom rom or de-enshittyify
From what i got from checking - there is not any rom already present, you can try to make one yourself, but that is a hard process
to de-enshittyify - you can start with UAD https://github.com/Universal-Debloater-Alliance/universal-android-debloater-next-generation.
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first boot into phone (and dont connect to internet) and enable dev mode
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then connect to desktop and open UAD, and it will give a long list apps which you can consider from removal (with deifferent degrees of recommendations)
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you may also disable remove google play services at your risk (google apps, and banking stuff would not work, but better battery life and privacy)
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after doing this, also remove any xaomi skin apps (can be done with UAD, in case it does not find anything, check the unknown section too) (phone, sms, message, ....) these are usually forked from aosp, but with added "features"
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replace these apps with fdroid equivalent (a good family of apps is fossify https://www.fossify.org/, and also use newpipe)
I am a bit experienced, so I can do it all in 1.5 hours, if you have not done this before, maybe 2-3 hours, and you will have a clean phone, largely devoid of closed source apps