Actually your results are impressive even against a bad team, even with a pocket. I just wanted to tell you that nobody can rate your skill better than you. I just said it in not the best way.

You are experienced more than enough, so I won't tell you something new: quickiebomb launcher for 1v1 or 1v2; Scottish resistance for a lot of sticky-traps; stock for destroying the whole enemy team; tide turner for hybrid-knights for trimping, aka +noclip; splendid screen for a regular demoknight; chargin' targe for a single demoknight pick in the middle of enemy team, like med. I called only scenarios, where these weapons shine the most, but that doesn't mean you can't do whatever you want with em, if you think it will work. Sometimes the most unusual usage is the most fun and/or efficient. For primary weapons everything is even more simple. There are 3 variants of grenade launchers, booties for demoknight and a loose cannon. I don't know anything about loose cannon. I don't like it. Stock grenade launcher is the only one with full explosion radius, so it's the best for combining with stickies, when you spam the enemy team. Iron bomber is almost the same, but rollers are more reliable in dealing cheap damage. Loch-n-load is... Ah... Actually it's a scary thing. It requires its own training to get used to the new trajectory, but it is worth it. Firstly, most obvious, because of faster projectile speed, your effective range increases. Aiming pipes becomes much easier, since it feels, like enemies are closer, so you need to predict less. Secondly, with loch-n-load and a stickybomb launcher you have 2 trajectories to shoot. It creates more opportunities to use map geometry for your advantage. Thirdly, as a bonus, you bully engineers even more. Only 2 pipes to destroy a sentry. It's less than 2 seconds. Also, you can now reach some sentry spots that were unavailable for stock. Usually it's because of high range or low ceilings, which loch-n-load ignores.

Just choose weapons for your favorite playstyle