So that was the dumbest thing. I have a love-hate relationship with OpenVPN. When it works, it works WELL. When it doesn't, it's usually because of some obscure incompatibility with network devices or a cryptographic oversight on my part, since I've been configuring it and setting it up for the better part of seven years. Anyways, that's just me bitching - I figured I'd put the relevant information here in case some other poor, lost soul has this issue.
I was getting the following error message on OpenVPN 2.4.9 on Windows x64 (Server 2019 Essentials):
Wed Nov 25 00:38:30 2020 us=37816 MULTI: multi_create_instance called
Wed Nov 25 00:38:30 2020 us=37816 192.168.1.23:51026 Re-using SSL/TLS context
Wed Nov 25 00:38:30 2020 us=37816 192.168.1.23:51026 Control Channel MTU parms [ L:1621 D:1184 EF:66 EB:0 ET:0 EL:3 ]
Wed Nov 25 00:38:30 2020 us=37816 192.168.1.23:51026 Data Channel MTU parms [ L:1621 D:1450 EF:121 EB:406 ET:0 EL:3 ]
Wed Nov 25 00:38:30 2020 us=37816 192.168.1.23:51026 Local Options String