Increase In Spam Since Switching To Spark

So sometime either last 2017 or early 2018 I decided to start using Spark vs the stock on iOS and eventually transitioned to using the Mac app as well. While I generally like it I have noticed one issue and I can’t help but think this must be something with Spark. I’ve started to receive actual spam in my inbox on an increasingly regular basis. Now I’ve Gmail since it was invite only and I can not recall ever getting any spam in my inbox. It’s probably happened a handful of times in a decade plus. I started noticing fairly soon after using it that what started as a once or twice occurrence per month has turned into a near daily issue of marking an email as spam in the app. What started me thinking this may be the app other than coincidence is when I started at a new company. This is my first job where I’m allowed to have email on my phone but according to their support documents we could only use the stock mail app as apps like Spark (even iOS Outlook) store emails in the public cloud and that is an issue with their security.

Am I crazy for thinking this is Spark or is there something to my thought process?

Looks like their servers log into your email provider in order to provide extra services, etc.

It depends on the accounts Spark is using. If you had mail forwarded to gmail, then Google has been doing spam detection for you. If you now use that account with a mail client, rather than sending to Google, you would see an increase in spam.
I had this situation when I started using a mail client instead of forwarding through Google. I bought SpamSieve and use that with my mail client. Seems to work well.
My motivation for doing this was that I don’t like Google reading and harvesting info from my email.

So am I understanding this correctly even though I use an account since switching to Spark, Spark is now doing my email spam filtering vs gmail doing the filtering?

No, different situation.
As far as I know, your gmail email should be spam filtered as if you were using the web interface, or another email client.
Sounds like you might be on to something.

I’m using Spark on both ios and macOS with gmail, and haven’t noticed any difference in the amount of spam. Perhaps using my own domain rather than an @gmail address is another level of protection against spam, as I rarely get anything through irrespective of the app I’m using.