Buy rtx 4090 vs running Comfi UI on cloud computing? What are the main differences in your opinion?

Hi guys so I was thinking to buy rtx 4090 for so long now but couldn't due to many reasons.

Some suggested me to by rtx 3090 bc it seems like a value to money thing. I could buy rtx 4090 but I'll need to upgrade my whole pc as well, as my current specs will bottleneck 4090.

It'll be huge upgrade for me and it's already been like 6 months of me delaying that. (I'm regretting i missed so much in this time)

I mainly want to run flux suite, stable diffusion, control net features, train my own loras, fine tune flux models on my data set, creating consistent characters (iPhone like photos) and Upscaling (i can't tell how much money I paid to online Upscalers already Leonardo Ai, krea, Magnific) so basically Image generations overall.

Comfi Ui is what I've heard of is an awesome start. The nodes system is fascinating for me to learn but I'm all set to dive in and give it my all.

Is it possible to do everything I could do locally, using cloud computing specifically the things I mentioned above? Using a rented gpu? What are the main differences in your opinion?

Anything you can suggest me to learn and use comfi ui as a beginner (it's mainly the nodes that kinds of overwhelmed me) i have an idea that i can load premade workflows but anything you guys can suggest me regarding that.

Thanks alot for taking the time reading all this 🙏