Honda Accord 99, 275K, Radiator leakage and engine heat up?

-Replaced Radiator
-Engine Temperature Gauge, don't work as it was working before heat up temperature showed 40% which was before 25% when you turn on the engine in the morning after 8 min.
-Changed genuine tempostat bought by Honda dealer
-Now noticed on long running gauge goes up to 65%
-Checked fan, both fan turn on when I made engine heat up by accelerating but it worked around only 30 second even I'm keep accelerating the engine
Please advise what do I do next. Is that engine related issue?

Temperature sending unit. It's what sends the signal to the gauge and what turns the fans on

Possible the heater core is corroded or blocked.

The motors on your fans are dead or maybe the fuse. Your fans don't seem to be working correctly.
make sure that when you replaced radiator that you fill it with coolant correctly and using only one color. Don't mix colors. Also turn on your heater when your refilling