Short answer
No. Light Ark is always free: no paywall and no subscription. The church says it will not begin charging individuals for its core pastoral care and discipleship. Light Ark Church is a recognized 501(c)(3) nonprofit religious organization. Giving is voluntary, does not buy privilege, and does not affect what you can use.
Running the service around the clock has real costs, such as computing power and servers. The church relies mainly on voluntary giving from people who benefit and want to support the mission, and it says giving is not a condition of exchange. You will not be asked to pay to unlock features.
If you do want to give, the donation page explains how, and donations are refundable: email the church with the transaction ID and amount; refunds go to the original payment method within 5 business days.