Lexus LS 600h Cooling System Overhaul

It was already about three weeks ago.
I was returning home along the highway, a 200 km journey.
After driving for 50 km, I noticed that the engine temperature started to rise. This wasn't good, so I pulled over to the side of the road.
A quick inspection showed that the coolant level was low at the bottom of the radiator reservoir and there was leaking under the car near the radiator area.
On the highway, I remembered passing a gas station earlier. Checking the map, it was only 2.2 km away. I walked to get some coolant (some Flagman brand, but it was all that was available. Now I wonder why?! It would have been better to use distilled water).
A guy at the gas station topped up the car with what I got.
So I added some (hoping for the best). The leakage seemed to be less severe, but my hope was fading as the engine cooled down only slightly below normal levels.
Okay, let's try driving.
No miracle happened; after 4 km, the temperature started rising again towards the upper limit.
Another stop. Called an emergency towing service and rode 150 km in it to get home. The tow truck did a great job. I had a nice chat with the driver, making the ride go by quickly. In the end, I left my parents' place at 4:30 PM and arrived home at 11:40 PM. Not the quickest 200 km.
I got home and parked in the garage.
I had planned to take it to a service station, but then I got a bit of an adrenaline rush after watching some videos online. It seemed like not such a complex procedure.
So, I decided to do it myself.
Like last time with LS00h, I did a full overhaul of the cooling system: bought a new pump, belt, thermostat, and Toyota original coolant fluid. Get it done right once for all.

I thought about getting another radiator but the original is quite expensive. In the end, I decided to buy the genuine part from AVA (original).
Started carefully disassembling the beauty. Admittingly, it was my first time doing this so I went slow and careful.

Of course, there were some nuances and particularly two bolts at the base gave me trouble. But eventually, I managed to unscrew them all and remove everything.