In general, I’d say if you don’t enjoy a role’s playstyle, then yeah not playing that role is usually best; DPS will generally have the most diverse options for playstyles, so I’d always recommend that.
There are a few core elements to a tank’s kit that define the role;
• the first is damage mitigation abilities (including higher-than-average sustain). These are the things a tank uses to protect a team, or at least to draw fire and attention onto themselves.
• Secondly, tanks tend to do high damage at close range; there are some exceptions, like Sigma (who excels better at mid range), but generally they’re most effective in close-quarters.
• Thirdly, they tend have some form of CC ability, or CC tied to their ult; again, crowd control refers not just to hard stuns, but anything that forces an enemy to respect space (Roadhog’s hook, for example).
This combination of attributes makes them good at creating and holding “space”, which is to say, areas of the map. They tend to have some of the highest damage, they have the highest health, some of the most impactful ultimates, as well as their CC, to help in this endeavour; but the shorter range is a requirement.
If you need to control an objective, then you need to control that space; and if your best tool for controlling space is a tank, then you need your tank near the objective. However, if you have a long-range tank, then they simply do not need to be near the space they are trying to control; this creates a balancing nightmare.
Either the long-range tank will be so weak as to be ineffective at controlling space at long ranges, in which case there would never be an advantage to playing them; or this tank would be good at controlling space at long ranges, in which case you’d never play anything else.
Close range means more dangers; this is true of most every fight. Distance means you have a better view of the fight, you can more effectively utilise cover, and in general you’re safer; however you also tend to be less effective, because the enemy have these advantages too. At close range you’re in more risk; but so are the people close to you, so you can get more done. Apply this to a proper example; if you can cap Ilios Ruins by killing the entire enemy team from afar, with no need to get close to them, then you won’t ever actually fight on the point. Either this strategy won’t work, in which case this tank is useless, or it works well, in which case you’re throwing by playing anything else.