As far as I know it’s bio that isn’t as effective at hotter temperatures than 40. If you want the benefits of bio (which I think is mostly the bleach component but I could be wrong) that’s the temperature you should be sticking too.
If you’re not particularly fussed then you can use either at any temperature but the bio isn’t making any difference at hotter than 40.
The enzymes in biological laundry detergents (i.e. the "biological" component) have optimal temperatures below 45°C, so if you use them much above 40°C you'll lose the biological action and just have the normal detergent (also known as surfactant) action.
Detergents dissolve lipids (fats, oils, waxes, etc.), so they will break down bacterial/fungal/viral membranes and detach any lipid-based substance from your laundry. Modern laundry detergents are specifically formulated to work at low temperatures (20-30°C). Adding enzymes to produce a biological detergent will allow it also to break down some proteins as well as enhancing the lipid-digesting action. But the enzymes won't do this at high temperatures.
New washing machines are required by law to be capable of washing at 20°C.
Where you get stagnant water pooling (e.g. in washing machine seals and detergent trays) you're likely to get microorganisms proliferating. Because the laundry will have been rinsed, there will be very low concentrations of detergent remaining at the end of a cycle, so any standing water will be hospitable for bacteria & fungi to grow in. (Viruses can't grow outside a host organism's cells, so this doesn't apply to them.) The bacteria will form biofilms that are quite resistant to detergents, so the next wash cycle won't necessarily get rid of them. A very hot wash (i.e. 90°C) might help to get rid of these, but manually cleaning the seals & trays will be more effective.