Differences in Bohdisattva in Mahayana vs Theravada?

I'm sorry for yet another "theravada vs mahayana" post on this subreddit, but I'm really curious about the Theravada perspective as I mostly listen to Mahayana, particularly Tibetan, teachers on the matter. So according to my limited understanding, Mahayana sees the bodhisattva path as open to everyone, and it is the "highest" path essentially, where you cultivate bodhicitta until you can achieve rebirth as a bodhisattva, and come back to samsara in various forms, again and again, until all sentient beings reach enlightenment. This eventually leads to complete Buddhahood.

So I've heard that the Theravadins idealize the path of the arhat instead, as a precursor to Buddhahood, since ultimate, permanent enlightenment takes pretty much forever. But aren't arhat's essentially just a lifetime away from Buddhahood? And I've also seen that Theravadins see Bodhisattvas as essentially just a type of arhat while Mahayanists see Bodhisattvas as superior to arhats due to their bodhicitta and vow to keep returning.

So like, what really are arhats and do they have fully cultivated bodhicitta, meaning are they also essentially just bodhisattvas according Theravadins? I'm mainly curious because in my biased sentiments I see the strong emphasis on taking the Bodhisattva path as more selfless and compassionate than choosing to be an arhat but I'm sure I must be misunderstanding something because Theravadins don't strike me as any more selfish or less compassionate tbh.

Edit: Oh my goodness you people are certainly educated and thorough! Many thanks to all the answers and unfolding discussions, but I can't really reply to anyone as I have been terribly busy and every time I come back to this post I'm left just reading through comments and contemplating on their meaning. You guys are the best and I am deeply grateful for the further expansion in my knowledge of Buddhist philosophy, I wish I could give a lengthy and heartfelt thank you to every comment!