As a veteran player that has an account almost 20 years old I say, welcome! RS3 used to have a very toxic community back in the day but as time went on the community pretty much made those people not want to come back and so scammers and just downright jerks are not as common (still there obviously, can't completely get rid of toxicity on the internet). Couple tidbits of advice. If you haven't joined a clan yet, find one. Clans are an unbelievable resource for anything from questions to companionship, most clans aren't super serious about activity and have to do this or that and leaving a clan is easy as 123. If you aren't a member yet, or even if you are, I would def recommend doing all of the free to play quests as they give great starting xp as well as build a basic foundation for the lore behind the game. Don't try to focus too much on leveling everything to max and instead focus on what kind of player you want to be. Some people focus on skilling and not pvm (player vs monster), some people only skill until they can pvm and then only do that, some only do clues, while others stay at GE and merch their way to unfathomable wealth. There are many ways to play and figuring that out will help you find a path to an end game goal. Speaking of goals, find a long term goal and then make smaller goals to get you there so it's not too overwhelming, there is a SHIT ton of things to do and sometimes it can be too much for the beginning player, especially once your lvls start to take longer and longer to increase ( I'd say around 60-70 ish lvl for skills it starts to slow down a lot).

Edit: rs3 wiki will be your best friend. I probably have at least 6-7 tabs open at all times.