That's a side effect of getting yesclip. To switch weapons you need to bind your weapons with the use weapon command.
Open the console and bind the ones that you're going to use throughout the run:
bind "x" "use weapon_crowbar" bind "x" "use weapon_pistol" bind "x" "use weapon_357" bind "x" "use weapon_smg1" bind "x" "use weapon_rpg" bind "x" "use weapon_crossbow" bind "x" "use weapon_frag" bind "x" "use weapon_bugbait" bind "x" "use weapon_shotgun" bind "x" "use weapon_ar2" bind "x" "use weapon_physcannon"
Go to your advanced video settings, and put the High Dinamic Range in High.
Even then, if you somehow end up on that side you're better off just ASHing all the way into the slope at the end of the coast since it works 100% consistently, unlike the slope launch you're showing here.
It's not really useful since we rarely end up on that side of the beach.
The reality is that there's literally zero people interested in actually running glitchless.
Check my tutorial video:
Keep in mind timing and amount of saveloads can vary depending on your hardware. I'd say try 9 saveloads, like Taggart just said.