Razer Blade Pro 17 Refesh Rate + External Monitor

I'm interested in buying a Razer Blade Pro 17 this weekend as part of a sale. Specifications for the model are: Intel Core i7-10875H RTX 2080 Super Max-Q 17.3" FHD 300hz 512Gb SSD My question is what refresh rates can I select within Razer Synapse for the 300Hz display? I'm thinking 60Hz, 144Hz, 240Hz and 300Hz. (My current Razer Blade 15 has a 60Hz and 144Hz option). Also more importantly, I want to run an LG UltraGear 27GL850 27" 1440p 144Hz display off the Razer Blade Pro 17 via HDMI 2.0b, will this run OK at 1440p 144Hz or will I have issues? Thanks in advance.