You are quite right in saying air guns are an entity in there own right and they have become very effective in what they can do. Optics are another area that has made accuracy more possible to obtain particularly for those of we silver grey air gunners.
So much choice! I think you are right to consider the TX as buying a quality rifle makes sense.
Consider a PCP also as I find as do many here that one compliments the other.
No need to buy new unless you want to. Plenty of good s/h rifles out there.
If you can get along to The Boinger Bash you can try all manner of air rifles and there are always some good buys to be had.