This issue is with the Aurora store and not e/OS itself. Google has made changes, which effect Aurora anonymous accounts and are now ‘rate limited’. Everyone using Aurora Store in anonymous mode is sharing the same few Google accounts. To Google, it looks like there is a small group of accounts mass downloading the same apps (and a few random ones) over and over. Google responds by slowing down access to these accounts. The Aurora team is aware of this, however there are no solutions as of yet. The only thing that seems to work, is make a clean/dummy/throwaway gmail account and sign in Aurora that way. This ensures better stability and gives you the full potential with the features available in Aurora Store. This is the only known workaround so far.
Using the default session installer in Aurora is fine.
Is there any reason you are not wanting to use the e/OS App Lounge?
Other appstore options would be ‘uptodown’, ‘aptoide’, & ‘apkpure’ to name a few…
Obtainium is another option…
Video Overview
https://www.youtube.com/watch?v=JiN37bn0OE8
Obtainium allows you to install and update Open-Source Apps directly from their releases pages, and receive notifications when new releases are made available.
Obtainium
https://github.com/ImranR98/Obtainium
This is a known issue with Aurora and has been reported in Github
https://github.com/whyorean/AuroraStore/issues/39