They make weatherproof aluminum junction boxes such as a Bell or Red Dot, with matching blank lid. To avoid box penetrations, their mounting screws attach to "ears" that attach to the outside of the box. The holes are threaded, as for pipe.
To enter a cable into such a box, take a specimen of your cable (or its measurements) to a proper electrical ...
I wouldn't use a screw terminal block.
Assuming this is for ordinary AC/DC cabling and not high speed data cabling I'd use Wago or similar connections. They're considered maintenance-free, unlike screws which can loosen over time. And enclose in a suitably IP rated enclosure.
But if this is a commercial ...
You can get waterproof junction boxes - look for an IP rating.
I would consider soldering - I soldered many wires in the middle of farmer's fields - just need a suitable heat source or a low voltage soldering iron.
I've fulfilled customer requests for overflow trays in cases of integrated laundry equipment, for example. You'd essentially install or build a shower pan (with all the same drain plumbing). What type and profile is appropriate depends on the situation. I wish my dishwasher had one as a one-time overflow recently did significant damage to my kitchen floor.
Water heaters have pans. You place the pan under the water heater, then attach a hose to send the water someplace less damaging.
You can also get water sensors, which rest on the floor and sound an alarm if water is detected.
There's less stuff for dishwashers and washing machines, as they only contain water when in use, and there should be someone nearby ...
Some of these are supplied with “stop leak” hoses on their incoming supply pipe.
Also some washing machines have the base designed with a “dip” with a sensor to turn off the internal valve if it senses water - caught my ex-wife out for a week until number one son looked at it :) ...
[I] noticed there were gaps in the caulk between the board trim (see image below) and the window, so I re-caulked all the windows
Gaps between the board and trim are normal. The standard way this is done is you have your siding in layers
Siding board (OSB)
House wrap (plastic or tar paper)
Window tar flashing (bottom)
Tar flashing (sides and top, ...