its possible that the filter is defective, unlikely but possible. Its more possible that either the plate has some type of deformity (scratch, burr, gouge) or that you got a piece of debris under the rubber gasket when installing it (been there done that).
As to tightness, hand tight should be all it needs. I do know guys who would put the wrench on and give them a "slight" tweak but nothing more.
remove the filter (if not already off), wipe the plate down really well and inspect it specifically where the rubber gasket makes contact, assuming you dont find anything wrong, install a new filter ensuring to lube the gasket with clean oil, carefully stick it up there and screw it on. I think your problem will go away, however if it doesn't, you have eliminated the filter and perhaps the sealing surface.
as to putting a new gasket behind the adapter plate, it isn't super difficult, hardest thing is cleaning off the old gasket from the engine side and many times the gasket comes off clean (other times you are up there with a scrapper)..
Don't overthink it, start simple and work through it one thing at a time.