What to do with a 2018 Lincoln Navigator?

I have a 2018 Lincoln Navigator that I bought new in 2019. It has given me nothing but headaches since. It now has close to 270k km on it and the yellow check engine light is on. The (trusted) garage I have sent it to has said that it requires a complete engine rehaul - new timing chain, new piston heads, etc. That can cost upwards of 10k. The other option is to replace the engine altogether. He has sourced a used one for me for 13k and will have all the work done for around 18k.

About 3 months ago, I spent about 30k to completely redo the suspension, fix cosmetic interior issues, and a bunch of other stuff.

Are these prices reasonable? Does it make sense for me to do this, or should I just run the car to the ground? Given that I've already invested so much money in it, should I have this repair done and continue to drive it for the foreseeable future?

Any help or advice is greatly appreciated.