Just Put all to Ripple (XRP) and Tron(TRX) these 2 coins are the most promising ranking coins because they did not meet another ATH this year in which not normal for a popular and promising project.
make it equally divided for best result in the future, at least 2-4 years from now.
Personally, I don't want to gamble in XRP right now until SEC case finally dismissed. The most solid coins I can see a big potential to explode more in the coming years are ETH and BTC, but as you said you want all that 30k in one single coin so my suggestion is in ETH. Wait for eth 2.0 and this coin will skyrocket to 6 digits very fast.
lately a lot of people have complained about the fees from ethereum, but the price is still in the $4k range. however, if ETH 2.0 had a very low fee, I think it could go a bit higher than this. well, that's pretty good to have with $30k for now.
however, looks like the OP already had his choice seeing him posting this in september.
as a note, if anyone still wants to find coins that have high potential, and doesn't want to look for deep information, then just choose popular coins in CMC.