I’d suggest to look for a local printshop. I print postcards for meetups regularly and work with a local business where I have better options to customize the postcard finish and the postcards are ready in a week. However, there may be a limitation of a minimal number of cards per design
Only downside is they are a bit small. But the printing is always on target. They also have 50% off sales fairly often, and if you sign up for Zazzle plus, you pay one annual shipping fee. Which if you order often, saves a lot on shipping.