Yeah I get that but the way I experienced it is that ads can appear in a podcast in any of the following three instances:

• Podcaster themselves record the podcast, may or may not add advertisement (self-spoken in their language)
• Podcast network which the podcaster is a member of adds ad break time codes, in which later ads are inserted, dynamically based on the listener’s location (pre-spoken, usually in the local language of the listener’s location, sometimes personalized)
• The podcast player/platform (Spotify, Pocket casts, antennapod etc) adds advertisements (also pre-spoken and in local or app language, more often personalized)

The podcast player’s ads can not be distinguished from the podcast network’s ads, except that they have a higher tendency for personalized ads (given that personalization is enabled in the privacy settings) or if the player declares it as an advertisement in a place where the podcast can’t. Or if you know that a podcast is on an ad free network. Other than that, you don’t really know if it’s an ad by Spotify or the podcast’s network.

My point is that, unless your player is explicitly declaring an ad as such, you cannot diatinguish a podcast network’s ad from a player ad. The only proof I have to know it’s a network’s ad in my case is that my player is open source and ad free. If I used a closed source commercial player, I wouldn’t know from who the ad is coming when it’s in my local language.
I’m German too and got German ads on english podcasts, but I know that the player didn’t insert it, so you can never be too sure if it’s Spotify adding them either.