4 trades at once is not that much but the tolerance level varies from one to another so if someone can't able to manage 4 trades at once in day trading then they can go for two and analyse they made profits or loss with the basic changes.
I will not recommend to different types of trading like futures and options, binary these are not really trading more of gambling so sticking with spot trading will reduce the risk to low.
Definitely not, back when I first got into trading and wanted to learn how to be better, I did as much as 50-60 trades per day, some of them profit, some of them losses but at least I was learning, the more I did the more I learned, both from the profits and also the losses as well, I learned more from the losses than I learned from the profits. However, there is one thing that I need to make sure, which is the fact that we are talking about something that takes a while and that should not be easy.
I personally hope that the best thing about crypto is that you could trade as little or as high as you want, and that would be your personal option. Do not limit yourself like OP says of course, but do not force yourself to trade more neither, if 4 is a lot, then it is a lot, no need to force it.