Finding a cost effective Tuya water timer that can be converted, has been a bit of a hit and miss.
Earlier this year I found this Water Timer. Price was about $60 AUD from AliExpress. The Timer itself uses the TYWE1S module and consists of a single button and relay to control the valve.
Model: FJSJKZQ-TY-W-XV-JS (PCB Markings)
I have been running the timer via the regular Tuya integration with Home Assistant, but had the odd event when it failed to turn off.
The original vendor listing isn't active, but I found these links.
TuyaSmart Life Store
Device has LED (red), Button and relay. The Green led is linked to the valve state and not controllable independantly.
Set red led to reflect WiFi/MQTT connection state (optional)
Automatic turn off after 15 minutes (900 Seconds)
Rule1 ON power1#state=1 DO RuleTimer1 900 ENDON ON Rules#Timer=1 DO Power1 off ENDON