You asked
Is the tamron 70 300mm f 4 5 6 3 di iii rxd good for wildlife?
Here is what the site says about that.
From Tamron 70-300mm f/4.5-6.3 Di III RXD: Tamron 70-300mm f/4.5-6.3 Di III RXD: A zoom lens by Tamron for Full frame cameras, 70-300mm f/4.5-6.3. A light, inexpensive telephoto zoom that relies on in-body stabilisation. Specs - Maker: Tamron - Focal length: 70-300mm (zoom) - Maximum aperture: f/4.5-6.3 (it gets darker as you zoom in) - Made for: Full frame sensors - Mounts: Sony E, Nikon Z - Stabilised: no - Autofocus: yes What it frames like - On full frame (Sony E, Nikon ...
From Lenses: Your first lenses: 1. A standard zoom, 24-70mm or 24-105mm equivalent. The kit zoom is fine to start. 2. A fast standard prime, a 50mm f/1.8 on full frame or a 33-35mm f/1.4 to f/1.8 on APS-C. Low light, people, food. 3. Then add for what you shoot: a telephoto zoom for wildlife and sport (wildlife and sport), a wide zoom for landscapes (landscape), or an 85mm for portraits (portraits).
Quoted from this site's pages.