If your competing under rules that require using hardware like a wheel instead of software to fill the gap for jumping half-life leaves behind, just add some more hardware to your setup:
Tape two of your keyboard keys together when you speedrun or have a special keyboard/key caps you use just for this running. For example if you use “t” to switch to grenades link your “t” and “y” keys together with hardware (ie, tape, glue ect.) then use >bind y “bind mouse2 +attack”< so whenever you switch to grenades you’ll also press an adjacent key that you linked via allowed hardware modification.
Then do the same for another weapon like the shotgun that will bind mouse2 to whatever you have it on normally.
Basically if the rules you want to compete under advocate hardware instead of software, use hardware instead of software.
Or just disregard this arbitrary nonsense and use >bind t “weapon_handgrenade;bind mouse2 +attack”< ect.
Or, and I’m not advocating you do this, but you could also just use the bind above and say you used a hardware mod or manually pressed two keys at the same time and no one would ever be able to tell the difference. Ie the arbitrary 1.07 half-life DLLs plus injections page at speedrun.com rules, that were mostly decided on by 5 people new to competitive goldscource and half-life speedrunning, are completely unenforceable and most people could already be doing stuff like this anyway and no one would ever know.
OR, just use software for auto jump like the btx injection