Not as bad as you think it will be, but still challenging.
I grew up there so let me chip in
Money can solve a lot of problems. You’ll never learn Tamil because it’s way too tough to learn without having spoken it at home but like all things, you’ll find a workaround with the working class. There’s an increasing population of Nepalis that are expanding base in Chennai. Look for this kind of domestic help
For Uber type situations, learn basic Tamil. Like inge vaango, inge stop panninga and you’ll be fine. In general their grip of English is way better than the hostile pricks in Bangalore.
And lastly the upwardly mobile class is super chill. You’ll have a great time. Weather be damned but no traffic, great QoL, great food, and overall affordability means you’ll genuinely end up liking the city. Great place :)