What has fundamentally changed?

I'm new to the crypto world, and I'm looking to be educated. I'm trying to figure out what has changed about how bitcoin functions since the price spike in late 2017. Obviously, the bitcoin system was under a ton of stress with all the newfound interest and high volume, and serious transaction delays and high fees (i might be wrong about that part) occurred as a result. This made the product essentially unusable for its intended purpose (making transactions). This seems like a problem, and I assume the bitcoin team is way ahead of me in identifying it. It's like a race car that has this incredible new propulsion technology, but once the car gets to a certain speed it starts to slow down, defeating the entire purpose of its existence.

So my question is this: What has changed about bitcoin since 2017 that would prevent the same problems from occurring in the event of another massive bull run? I feel like, as a concept, the sky is the limit for bitcoin, but I'm curious if the technology has been improved enough to rise to the occasion. Thanks.