You’d have to have it done by a third party.

• m on 14.8.1 and do not want to update)

Unless you are jail broke. There is no valid reason not to update. And lack of security updates make it a reason you should.

Also as said you can use a third party. But it’s likely you’ll lose Face ID and True Tone.

you wont lose face id and wont lose true tone if you are very careful not to damage the camera and not to damage the camera cable

Face ID has to be paired to the new screen. Most 3rd party places don’t have the software to do that.

does op want the face id to be working ? i thought front camera ensemble security control by logic board

The Face ID has parts that have to be linked to the logic board. You can’t do that without special software from Apple.

hey as long i can use 4 digit passcode for apple wallet , i really dont care face id if i replace my screen display

Your iPhone X is acting up anyways, I don’t see what you have to lose by updating to the most recent iOS? 🤷🏻‍♂️