Gerrymandering is an issue precisely because of winner take all. In a proportional system the definition of districts (if they exist at all) doesn't have the same effect on the outcome of the election.
In fact, the best solution to gerrymandering is adopting an electoral system (proportional) that isn't susceptible to gerrymandering.
For example the mandates might be distributed proportionally globally or per district. In the latter case gerrymandering works when you have rounding problems (10 mandates per district and one party has 9% of support). There are also usually thresholds under which you don't get to the parliament altogether, and the "wasted" votes are distributed proportionally between the other parties - so again, gerrymandering still works when this is done per-district rather than globally.
This is exactly the situation in my country (Poland), and gerrymandering isn't a thing mostly because of people looking at it as corruption and protesting whenever some government tries to do it (last time it was PIS trying to change voting borders to add a lot of PIS-voting countryside to the capital city to finally win elections there :) - after protests they didn't do it).