Harman p35i vacuum issue

I moved into my house in 2017 and the stove came with the house. We didn't use it the first year because we didn't know anything about it and find that it was installed without permits being pulled. 2018 we had a tech come out and teach us/checkout the install and all was great, he told us that the stove had hardly been used.

Each year since, we burn about 3 tons through a winter, do regular maintenance/cleaning which consists of weekly quick cleans to remove ash and clean the glass and longer periods between pulling the insert out cleaning the flue and a deep cleaning on the insert.

This year we started encountering a 2 blink status that started to come and go and now it won't go. At first I thought I hadn't cleaned well enough, I went back over the entire insert and exhaust, got up on the roof and banged on the cap to clear up any exhaust issues.I replaced the door gasket, and checked the new gasket with the paper trick and all is well. I replaced the fines cleanout door & gasket. I replaced the vacuum hose between the pressure switch and the fines box. I replaced the pressure sensor itself. I've replaced the control board because at one point it was doing a real funky light sequence and fans were turning on/off without rhyme or reason. This past week I replaced the ash box gasket (what a pain in the ass!).

Today I cleaned it up again, opened the fines door, vacuumed out the cleanout and used an air compressor to blow away the dust I couldn't get out, I removed and reseated the vacuum test port screw in the left hand side of the firebox and it still won't light!

I've also jumped across the pressure switch with alligator clips and the stove starts up. At this point I'm going to replace the whole damn stove with a new one because I can't figure out where the vacuum leak is! I had the technician who we've used to clean the stove and service it in the past come out and look, and we've talked about the components I've replaced and why and we're at a loss. I have no idea what's wrong with this or where to go from here. Any help would be appreciated!