To do two things at once is to do neither.

Attention does not divide, it alternates, and every switch costs a little of what was loaded. Two tasks running together each get a degraded version of you, and the degradation is hardest to see in the work you know well, because it still feels fluent while the mistakes go in. What you save in elapsed time you pay back in the parts you have to redo.

Choose one hour this week and give it to a single thing with the other inputs closed. Notice how much further it gets than an hour of the usual mixture. Then decide which tasks are worth that treatment, since not all of them are.