^^^ depends on how precious is the key I think
The wood needs proper protection, resin all over to properly soak in and sand back, then quality paint would be ideal.
Sausage's method is not the gold standard....
But on the other hand its 10 y/o already, sanding back an expanse of resin to be
proper flat is not ideal for a beginner, and what are we trying to achieve? Water tight and another few years maybe?
So whats your priority?
OH yeah, and its not a dodgy repair, that was normal. It was thin paint over wood with a 'do not expose to the elements' warning