I’m a realist.
...
The OP Fleet is probably covered head to toe with Leviathans with high Relic characters + max ships.
So, you're a realist, but you're gonna go with what you imagine is true. Understood.
It would take years and quite possibly thousands of dollars for the OP to catch up with the vast knowledge, skill, and ships these players possess.
Uh, no. This is not GAC where you need to match your opponents on multiple fleets at the same time. You only need one good fleet. While there are cutthroat fleet shards, and it is possible that the OP is in one, the majority of shards are ... not that.
Furthermore, it just doesn't take that long to get Executor. Razor Crest is the only hard-to-farm requirement. While it does take time to build up all the relic mats to meet the prerequisites, it does not take "years". 24 months is a very, very long time in this game. You are way off.
Please do not give out misinformation based on your fears.
Actual farming time for different resources can be estimated usefully using a spreadsheet and tracking one's actual progress or using one of the many calculators for SWGOH players available on the internet (though these don't include unexpected additions, like double drops days).