Hello Kyrie,
Performance of a Mendix application involves analyzing different aspects :
1.Database Queries and Indexing
FYI:-Reference
Forum : https://forum.mendix.com/link/space/app-development/questions/112926
2.Microflows and Business Logic
FYI :- https://docs.mendix.com/howto/monitoring-troubleshooting/detect-and-resolve-performance-issues/
3.Widgets and UI Design
FYI : https://docs.mendix.com/howto/monitoring-troubleshooting/detect-and-resolve-performance-issues/
4.Mendix Version and Modules:
Overall Documentation : https://docs.mendix.com/howto7/general/community-best-practices-for-app-performance/
Overall reference :- This blogs will may be helpful