You should start by adding the exact model name of your device to the post, otherwise its not possible to check anything.

Depending on the tablet, you might not be able to unlock the bootloader. I have a Chinese Lenovo model Y770 that's not unlockable.

You can always remove your google account from the tablet and install Aurora Store and f-droid to keep google from tracking what you're using. Every step in the right direction is a step away from google.

Using Open Street Maps, Mull, Brave, librewolf, various proton apps or whatever you prefer will let you get away from the built in google stuff.

GrapheneOS doesn't support it. If there are no ready-made custom ROMs for it, take a look at Generic System Images (GSI). Due to the lack of cellular modem (I assume), GSI have better compatibility with tablets and should only require:

• Unlockable bootloader
• Project Treble support (check with this app: https://f-droid.org/en/packages/tk.hack5.treblecheck/)

That said, there's still no guarantee it'll all work out. Feel free to ask for any details. I went through the misery of installing a GSI on my Tab A7 Lite since it had no LineageOS support and all of the existing ROMs were also GSI that didn't really fit my tastes.

Also, you're not alone if XDA forums tutorials are incomprehensible. A good majority assume some level of niche knowledge.

Lenovo tablets aren’t alternate OS friendly.

dude, I mean come on - which lenovo tablet? woulda taken you like two seconds to include the model. intel? arm? config?

A while back when I was considering buying one, I bookmarked the XDA forum about this device. Posting the link because noone has yet: https://xdaforums.com/f/lenovo-p11.12077/

what's the model number? have you checked out postmarketOS also?