I think it depends on how big your server capacity is. Most websites on the internet are run by renting servers. Only a few companies, like Meta, Google, have their own server to host. If a server can handle a lot of traffic, it should not have any problem handling those DDoS attacks. For example, have you ever heard that Facebook or Instagram, or Google are under a DDoS attack? Probably not.
I think I have witnessed a couple of Facebook (meta apps) outages that were attributed to DDoS attacks, so not system or service is 100% immune to such attacks. What the likes of Cloudflare help with is to reduce or mitigate on widespread attacks once they happen.
I think it all comes to how powerful or determined the attacker is. Some don't seem to give up so quickly.
These difficulties must be due to a recent outage on Google Cloud, at least in South America it happened this week. I don't remember the day. So these instabilities on the site could be DDoS but they could also be difficulties with the providers, in this case Google Cloud.
I honestly don't remember when last i heard that platforms like Facebook, Instagram and even Google suffer from a DDos attack, it's been a very long time I heard of such and I guess that must have been when the company was still growing, even the google outage you are talking about is also something I know nothing and have heard nothing about, except there is the possibility of the platform experiencing an outage in country or continent while it's available in another.
X (previously known as Twitter) on the other hand have experienced serious of outages a couple times even in last month two months or so, I don't know if it's as a result of DDos attack or something, but then, I am still wondering what those people behind such attack gain from it... 🤔
As I said, I think this happened more in South America. It must have been some specific error here. So if someone had problems accessing a website recently, Google Cloud probably had something to do with it.