‘Modern engines’ can go back a long way now, 80’s onwards could do 100k+ it was normally rust that got the car first. I think only my 80’s Polo’s and Fiestas came with tachos that only went to 99999 before rolling over.
I have 4 cars that all run as intended, 3 are tax/mot insured the other is having work done but not engine related.
1989 Golf GTi 8v 97k - having suspension and brakes done.
1989 Golf GTi 16v 139k
1994 Corrado 2.9 VR6 210k
1999 Toyota Altezza RS200 118k which is my daily car.
So with general maintenance and basics like checking the fluid levels more often then a new car which you rely on the dash to tell you to look it’s not difficult. Welding is the expensive part.