Good day!

This is my first time posting in this forum and I am still a newbie regarding PCs.

It has been a month since my father and I bought this PC (we haven't bought a GPU yet due to the crazy prices right now). Everything is fine until I thought about the power supply we bought, which is a Corsair TX550. I'm currently worried because the PSU we bought may not be enough once we're able to buy a GPU. I've tried power supply calculators like Cooler Master, BeQuiet and Outervision, but I can't still figure out whether this PSU is already enough because other people say that some PSU calculators are exaggerated.

Here are the specs of my PC:

Processor: Intel Core i7 8700
Motherboard: ASRock Z370 Extreme4
RAM: G.Skill Ripjaws V 16GB 2400MHz (2 sets of 2x4GB)
CPU Cooler: Cooler Master MasterLiquid Lite 120 (1 fan)
Case Fans: Raidmax R120TP (I have 3 of them, I might add another one soon)
HDD: Seagate 1TB (7.2K RPM)
SSD: Adata SU800 256GB (I will buy this along with the extra fan soon)
Optical Drive: Asus 24x Internal DVD-RW
GPU: Asus ROG Strix GTX 1080 Ti (This is our target GPU but we don't have it yet)
I don't have other accessories like RGB strips or what. I don't and I won't overclock anything too.
I usually use my PC for 14-16 hours per day.

I really want to be sure if this PSU is enough for the GPU so that I can decide whether to save for a 650W/750W or not.

Thank you.