It's more complicated than lenders opposing inflation but debtors favoring it. That only works if people are pure lenders or pure debtors.
In reality most people carrying significant debt are people who are strongly affected by inflation of the prices of goods and services, and most people and institutions who are in a position to lend are not as affected by such inflation.
The most at-risk people are those who are both in a lot of debt and also affected by the rising cost of goods in services. This can be anyone carrying a significant mortgage payment (as a % of income) and supporting a family simultaneously. High inflation hits these people especially hard because pay raises and real-debt-dilution often do not keep up with the rising costs of goods and services.
This can cause a great deal of financial fragility in the short term, even if the individual has good long term prospects due to inflation-based debt dilution.
Which is why corporate media has apoplectic fits whenever interest rates go up or unemployment goes down.