I usually invest 70-80% of my assets in Ethereum.
This is a one way of beginner's mistake and this may be the right time for converting your ethereum or altcoin investments into bitcoin. Instead of doing with ethereum or any other altcoins, you should do for the same 70-80% with bitcoin for securing your future. If you are a short term player which is the reason why you are dealing with ethereum, in my opinion, you are again making another blunder mistake. Realize about the true potential of long term planning with bitcoin and plan up for conversion as soon as possible.
I would agree but I would say 50% bitcoin is enough, then 25% ethereum, and the other 25% should go into bnb and ltc a bit, and the rest could go to whatever you want. I would say 10% on bnb and 5% on ltc and the other 10% on smaller stuff that they want to invest into. That would make it 100% and would also have 75% on guaranteed good stuff, even 85% if you consider bnb good as well, it's at the top at least, third biggest altcoin.
So all in all, I agree with you that bitcoin should be biggest, but having 70-80% on bitcoin is too much, it should be a lot less, and that way it would make a lot more money and it would definitely be something profitable in the long term if you wait for like a decade.