Unlimited ram? Sorry, there will be no provider. The only other things you would need is a few prossers and some MOD/plug-in soport and you could create a server with infinite Poeple, MODs, plug-ins, worlds, extra. Shockbyte.com has good rates great 24/7 customer support DDoS protection, MOD and plug-in support extra. Artonos has 3 problems: 1. Customer support trash 2. The server is only up for 3 munites unless somone else joins then it resets the timer (I might be wrong I got that from my freind) 3. No DDoS protection. Minehut idk too much about but I am pretty sure they give trash RAM for the free plan and not very worth while prices. Their customer service I have heard wonders about tho.

Aternos

i dont have a free hoster but if you want you can get a cheap server hoster called Pebblehost its on 24/7 and 20 tps

There's 2 well known server hosters that host servers for free:
Minehut
Aternos

Out of those 2 I recommend minehut more because it doesnt have a queue, and my personal experience with it is better than aternos (assuming you have less than 5 friends).
I cant really comment on PloudOS like MCserveradmin mentioned, but it has more ram than minehut (idk abt Aternos), however it also has a queue for which priority is based on country.
So if you live in a rich country like the US, probably use ploud/minehut
Otherwise you should probably use minehut.

Unlimited ram? Sorry, there will be no provider.
Every computer has limited ram and servers are computers. Anyways: I personally recommend ploudos.com as free server hosting provider. I know you haven't unlimited ram but if you and your friends play normal survival Minecraft it should work fine :)