3) Offer a different crypto payment options (mainly BTC / LTC / ETH / BCH)
Ouch! This is a difficult one.
The plugin should tick these criteria
Just a note; these criteria usually come with a running node too. For instance, as far as I know, BTCPay, that is mentioned above and it's very recommended from me, requires you to run a node, which is an extra cost for your business. The specific one allows lightning payments too which is nowadays considered a must for the customers.
For an easy installation of a BTCPay server with extras included check
Umbrel.