You'll go for your jewels at a shop I'll bet.

You can mark the wires and change the fuseblock yourself.
Its all push on spade lugs from underneath.
You need to make a tool to release the locking tab on the back of the
lugs used at the relay sockets.
When you swap over the relay socket lugs- you can crimp any lugs that
are spread open.
When I swapped my fuseblock I soldered a lot of suspect crimps.

There were a lot of funky problems caused by loose relay socket lugs in my car
that I could make come and go by gently pushing on relays. My power windows would be intermittant for instance and it turned out to be sloppy lugs for the
window relay.

Finally, you might notice how flimsy the contacts are for 30 Amp fuses.
It's some kind of miracle that the fuse sockets can carry 30 amps at all.
I relaced all of the fuses with new fuses since with repeated insertions the legs get shaved down and contribute to making the socket loose and ultimately
resistive which generates the nasty heat problems you witnessed.

Use dielectric silicone on the fuse sockets and relay socket lugs to deter corrosion. A local industrial supply sells a 4 oz. toothpaste tube supply of this handy stuff for maybe $6, instead of getting a gram for a buck at
Autozone. Look for your local industrial supply where they sell ball bearings
and hydraulic hoses etc.

It would really help your project if you get the Greenbook Wiring diagram for your year/model car.

Good Luck, Bill