Another off-the-wall tip from my old manufacturing editor's resources:

Electrically-conductive epoxies are showing up in a lot of industrial
applications, replacing solder. They may solve some problems for
hobbyists, too.

At the rist of sounding like a shill for MasterBond (again), I'll
suggest the following info from this epoxy specialist:

https://tinyurl.com/yda8bbmc

They have a good reputation.

--
Ed Huntress