Compatible RAM for my HP ZBook 15v G5

[HafizZawawi]

Hello there, currently my RAM is having a lot of problems and I am looking to replace the RAM, but I'm confused with the compatibility of my laptop and the RAM that I need to buy. I've used the crucial scanner app to find compatible RAM but I don't want to buy the Crucial RAM as I heard a lot of bad reviews.  I had check similar specifications with the recommended crucial RAM but I'm confused on some things. Somebody told me that I need to check RAM clock speed from my previous RAM, but if I wanted to replace the previous RAM, do I still need to consider this? Also what is the difference between PC4-21300 and PC4-2400, do I need to consider this? This are the specifications for my laptop (HP ZBook 15v G5); 

Processor: Intel (R) Core(TM) i5-8300H  CPU @ 2.30GHz 2.30 GHz

Installed memory: 8.00 GB (7.86 GB usable)

System type: 64-bit Operating System, x64-based processor

Online Information on compatible RAMS:

32 GB DDR4-2667 (ECC or non-ECC SDRAM)

(2) SODIMM slots supporting dual-channel memory

4 GB, 8 GB, and 16 GB SODIMMs (for Intel Core)

Up to 32 GB

Optional 16 GB SODIMMs in 2 slots

I wanted to buy some of these RAMs, but I'm afraid that it will not be compatible and I will be wasting my money, can somebody tell me if any of these RAMs are compatible or suggest other RAMs:

1.  Samsung 32GB (2x16GB) DDR4 PC4-21300 2666MHZ 260 PIN SODIMM 1.2V CL19

2.  CORSAIR VENGEANCE - 32GB: 2X16GB - DDR4 - 2666MHZ (PC4-21300) - SO DIMM 260-PIN

3.  Kingston HyperX Impact 32GB 2666MHz(PC4-2130) DDR4 SDRAM SO-DIMM 260-pin

I really need somebody's expertise to help me with these. Thank you.