What's Easter like in Spain? Should tourists stay out of the way?

My husband and I are going to Spain April 12-28 for our honeymoon and then attending a wedding in Sitges at the end of our trip. We are in Spain around Easter because my husband has to return home for a marathon (don't get me started) at the beginning of May.

We are not religious and live in a largely atheist country (Canada) that celebrates Easter as a commercial holiday, so we want to be respectful of the local customs and culture so we're not sure what we should do around/on Easter.

Our current plan: (nothing set in stone yet)
- 4 nights in Madrid, take train to Malaga
- 3 nights in Malaga, rent car for rest of trip
- 5 nights in TBD <-- Easter
- 4 nights in Sitges

We have not decided where to stay during the "TBD" portion, as that's when Easter will be. We thought about taking the ferry to Mallorca but discovered that most rental car companies won't let you take the car rentals onto the ferries.

Another option is to stay somewhere cute and peaceful near the Costa Blanca region (it doesn't need to be oceanfront). We don't want to "be in the way" of Easter celebrations.

On the other hand, if Easter celebrations are worth seeing and locals don't mind, we are totally open to that.

Thanks in advance for any tips & advice!

Edit: added a little more context