Hello, i'm in the same situation as you, but i almost finished what i want considering i just have to wait for my stuff to be delivered to France. Don't be worried, 150$ is a decent budget for a first keyboard espacially if the keyboard size doesnt matter (60-80%). If you prefer a 60% and if buying a 20 / 25€ soldering station isnt a problem for you you could get an ok60 pcb from aliexpress (26$ shipping inclued), it has QMK, rgb leds that you can desactivate and USB-C.
For the case you could get a 8-15$ plastic universal 60% case or go for something higher in quality if you don't want plastic. For the stabs you can get a pack of Cherry Stabs for like 8$ or a pack of everglide stabs for 15$. For the plate i would suggest aluminium for that budget : there are a lot of cool universal aluminium plates with a lot of different colors on aliexpress and kbdfans.
About your switches, you could also buy some Gateron Yellows, they're between Reds and Blacks if we are talking about the weight and they're very smooth, you can even order "Milky Yellows", they'll have a better sound and they'll be a little be more expensive. Considering the leds on the ok60 arent directly under the switches you will still be able to see the rgb if you like it even with non-clear switches housings.
So it would be something like 70-90$ including shipping if we dont talk about the keycaps and the lube.