Part of why I'm so happy with MCH (in frontline) is because they gave us back the damage. They want you more engaged in fights and not hiding too often. Your reward is BH5 early, which means a full return of that calculated attack you mentioned (if thats what you meant). Early on, don't focus on getting solo kills. Focus on doing damage and spreading that damage out so you can get assists and build BH. You'll have to adapt and learn when to follow up/secure kills versus when to do more spread damage for your team to capitalize, but don't overthink it. Spray and pray for assists, get your BH5, then eventually you'll realize you don't want to sit in the back getting individual solo kills on noob roulette players. You'll have the skill to time sniping BH5 enemy premade players who get over confident. BH5 comes fastttt.
If you time your use of role action, keep your map open, and watch spacing, you can become a killing machine. 15-0-30 with 2 mil damage isn't unexpected for MCH anymore.
Also, no one is really "looking" for your LB marker on them, or even expecting it. You said it yourself, getting shot doesn't even scare most jobs anymore, and if people are quick with the guard, take advantage of your LB distance. Wait for the guard timing to be up before popping. Having more than half health isn't enough to scare a squishy into healing usually, they'll finish a cast then maybe heal or shield, happens all the time. The fights are chaotic enough for you to get the combo off plenty, otherwise machinists wouldn't be top 10 kills and damage so frequently. My biggest issue this patch would have been the BH changes and bringing back secure (hate it, lol) but after playing it, I'm just enjoying MCH as best I can.
If you're stuck with bioblaster, I'm not sure if you're popping sprint after using it and before? You dont always need a good hit, sometimes its just good to cycle it, pop it on a tank thats too forward or someone diving, on someone in a barrier, get rid of it. There's so many opportunities to use it. Makes me think you're distancing yourself like an AST when you should be more middle of the crowd. I'm almost frontlining sometimes (badum tsss).