Where do I begins? What's the best wallet you're using? Where do I buy bitcoin with easy exchange without scams?
Finally, should I do it now that the price is not stable or I should wait a little in case it goes down again? We are all here to learn.
And the Decentralized exchanges are also numerous like Bisq, Uniswap, Pancakeswap, etc. And for your last query, there are 2 scenarios from you.
1. if you wants to accumulated BTC then it's mean it is for long term. and for long term this is the good time, because market is making some moves here, due to ordinals problem and due to some halts by CEXs and due to many other factors that needs no definition. As, in the long run we all know BTC will break its ATH and set a new one above $100k.
2. If you wants to hold BTC for shorter period of time like for 6 months or maybe more, then i suggest you to wait some time, because you might get better opportunities to enter market in coming months. But that's just my observation, so you should DYOR too.
Keeping the time difference aside, you must have to do DCA, as it is necessary in Accumulation phase. because if you think now is the good time and buy BTC from all of your fiat and in future BTC goes down and now you have no money to buy more BTC, in that case you will stuck and can't benefit from the bearish trend. So in accumulation you just have to fill you bags until you can by doing DCA and ones you think its time to forget about them. Then you should again start accumulating them.