I would recommend Gelid GC Extreme or SYY-157. Even better is PTM7950.

For the thermal pads, you can use putty, but definitely avoid K5 Pro. It's more a thermal paste than putty. Makes a huge mess and has low performance. There's this TG putty from amazon : https://www.amazon.com/T-Global-Technology-TG-A7000-Silicone-Type-Electronic/dp/B0BD6F2L79

If you can wait a couple weeks, you can find Upsiren U6 Pro from aliexpress, I'm using it and can vouch that it's good stuff. I haven't tried the green A7000 putty, but I've used TG-PP10 from the same company and it was quality.

For thermal putty, I would recommend avoiding K5 Pro, having tried it myself. There's better performing and far less messy options like Upsiren U6 Pro. Takes a couple weeks from Aliexpress but worth it. If you need something fast from amazon, this stuff is better than K5, not quite as good as U6 : https://www.amazon.com/T-Global-Technology-TG-A7000-Silicone-Type-Electronic/dp/B0BD6F2L79