River monitors for Ukraine's shallow waters

What kind of river monitor would suit Ukraine in the current war?

Use small shallow-draft craft in numbers, with a 30 mm gun plus anti-tank, mortar, and air-defence weapons.

Small, light craft suit shallow rivers better than heavily armoured vessels and can be built in enough numbers that one loss does not end the capability. A 30 mm cannon would provide general firepower, while anti-tank missiles, mortars, and air-defence missiles could be distributed across the force. The alternative of a 105 mm gun is mentioned, but draft, weight, and survivability still govern the design. The result is closer to a CB90-scale family of boats than a traditional heavy monitor.