It's understandable that some people don't find the OP MC trope to be interesting but there are some other draws in here I think. I probably agree with the objective complaints on the whole but I nevertheless didn't mind continuing reading. I can't really explain why the following isn't all that bad but in some seriousness I found this to be far more tolerable than most isekai trash.
My personal biggest issue is probably just early on when he's randomly just wandering around and somehow manages to arrive at the next plot event for no apparent reason. I'm chalking it up to divine intervention since that does actually seem plausible but the author leaves it kind of vague on that end of things. Due to that I think the overall tension is a little dulled since we come to expect the good guys to be relatively unscathed most times. There are major injuries and deaths that take place but as time goes on they either stop happening around MC or he simply heals/purifies/whatever to make things better.
I suppose I might as well comment on his intelligence/competence since that does seem to be an important factor for judging the progression of the plot. I find it kind of hard to peg what his actual knowledge level is supposed to be, or if the writers are even concerned with that and just do whatever is convenient for the moment. Most times he seems to be about the average intelligence of any working adult man though here and there he's probably a bit above average with his experience with programming or the fact he apparently still remembers what he learned in math class (c'mon, you know most people will just say they forgot). Beyond that it's a little inconsistent if he thinks logically or not.
I feel like we see some solid reasoning from time to time but other times it's like he just gave up on thinking and just leaves it up to random chance or luck. I do have some concerns with these moments because he tends to be careless with very sensitive situations or makes situations way more volatile for no other reason than I guess rule of drama. For all the times he's absolutely failed to pretend to be normal he only finds new ways to screw it up.