1990 Other Toyota Models Should I do a valve job or a rebuil

Engine Mechanical problem
1990 Other Toyota Models 6 cyl Two Wheel Drive Automatic 74K miles

I have a 90 Winne 3.0 V6 auto with 74k. Just before I bought it at 62k it burnt a valve on the right bank. The prior owner did a valve job on the right. Now, 12k later I have a burnt valve on the left bank. It burns no oil. Compression test is about 150 on all cyliners except the bad one, which is 25 lbs. It still has quite a bit of power but runs a little rough at idle. I am being told by my mechanic that the extra compression created by a valve job risks damaging the lower end, such as throwing a rod. They are recommending a rebuilt engine instead. Almost half a century ago I was a car mechanic. I did valve jobs all the time with no problems with the lower end. I am told that modern engines are different, but they look the same to me. What is the reality here? Can I do a valve job safely or are the telling me the truth?

Also, it is my conjecture that the fuel injection running lean is causing it to burn valves. It that accurate and what needs to be done to the FI to solve this? If not, what else could be causing it to burn valves

Thanks Larry