Welcome to the site.
Yes, throttles quit working in the rain. I've had two of them do it. Carry a grocery bag & a long kale tie if you're going to ride in heavy rain. A hair dryer repairs them.
Sorry Covid hit you so hard. I had the fever for 137 days but it wasn't worse than regular flu, just would never go away. Plus the desert dry nose for 2 weeks and couldn't smell food for 4 days. Being in aerobic good shape probably helped keep up the oxygen levels. No treatment prescribed but tylenol. I kept riding the bike as usual, just a little slower to keep my pulse rate down. My weight program (pilates) involves 5 lb hand weights. My body is designed for deer chasing on rainy WVa mountains. All legs, no torso.
I ride a geared hub motor with 80 lb of supplies up >80 hills up to 15% grade. 330 lb gross. A $221 ebikeling would start the weight unassisted on that grade. Now I have a Mac12t, less watts (500) but more torque. With those, & pedaling unpowered 80% of the time, my 8 speed chain lasts 5000 miles.
But you shouldn't have any trouble with broken spokes or rims on a R&M. My $1900 yuba also came with real steel wheels & real aluminum frame, but most wouldn't want a hard suspension cargo frame. I shop off the bike, the stretch frame balances the load best. With my weight on the front tire, high pavement separators & speed bumps never yank the bars out of my hands & throw me over the handlebars. (5 times on MTB & cruisers)
Hope you build your endurance fast. The body is built to heal, if the bugs don't kill us in the first week or two.