Q: Replaced Timing Belt/possible bent valve/misfiring in 3 out of 4 cylinders 2002 Honda Civic

Hello - if the timing belt was not replaced due to failure (and almost certain bent valve damage), it seems unlikely that simply replacing the belt/tensioner, idler, guides, etc. would cause the level of damage that is suggested. If compression was measured as even across cylinders, and within limits, prior to the timing belt service, there would be grounds to suggest there is a missing part of the story, where damage was done. At this point, you are down to "How much do you trust this mechanic/shop?". Given your higher mileage, it would be pretty-much impossible to prove damage, accidental or otherwise. Find out what problem codes are setting the "Check Engine" light. It may well be that the camshaft/crankshaft timing is incorrect as it is, and re-timing the cam puts you back in business. If the engine problem codes indicate a camshaft timing problem, I would first have a conversation with the shop that did the timing belt job as to correcting this. If that does not result in satisfaction, I recommend a timing belt service performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, correct this problem, and hopefully, get you back on the road successfully.