I know these are a lot of questions but any advice is greatly appreciated, this forum has been extremely helpful for a noob that has been in the space for about 4 months now.
One simple thing what I am similarly doing like you is, converting my profits from altcoins into stablecoins and then waiting for dips to buy more of the same altcoin. Please note I'm trading only highly reputed altcoins so I'm having confident about bouncing back of those coins always. Do not do the same for random coins as they may never get pumped again.
Do not trust any third party services for your money; there are a lot of such services are offering attractive interest but I never listen to them; keep your coins in your computer/mobile because only when you are holding privatekey, those are your coins.