I do feel for you Jimbo. You seem to get all of the networking problems windows can dish out.
I don't think you are bonkers. Unlucky I guess. Or perhaps you are the only person who mentions it.
I struggled with networking and made fstab like this (I forget where I got it from or I'd link it) and it works for me.
and /root/secret.txt like this. I use a MS account to sign onto Windows but I find using name and domain works better (more reliably) than putting in firstname.lastname@example.org)
# <file system> <dir> <type> <options> <dump> <pass>
UUID=b023985e-c449-4301-ae92-582e6d3c39b3 / btrfs defaults,compress 0 0
//192.168.1.100/Transmission /mnt/MacBook cifs credentials=/root/secret.txt,iocharset=utf8,uid=1000,gid=1000,file_mode=0777,dir_mode=0777,nounix,nofail,x-systemd.device-timeout=1 0 0
I'm not saying it will 100% work - just it does for me.