Just a thought but could it be your fuseable link ? It’s the smaller wire coming off your positive battery post clamp. If it is that’s a really easy fix ! You could just disconnect it and use another wire as a substitute to see if there is any changes in your issue.turn key on and try your switch’s then try and start it But DO NOT LEAVE IT THERE for a long time only a minute !!!! You are only testing with the wire to see if you get power. The fuseable link works like a fuse for your car if you have a dead short , it burns out before your car burns down. I have had my fuseable link go on me and it took me awhile to figure it out , I checked everything before I checked that. I hope this helps , good luck.
