As a cyclist and interested in doing the same, I would point out that the industry is rather large if you know where to look.
bike companies are okay, but the thing about cycling is all the parts come from specialist suppliers and so you can invest in the companies behind key-tech rather than just a bike supplier on the whole.
for example: continental are in the automotive industry, but are also a big name in the manufacture of quality bicycle tires.
Garmin and Wahoo are big for their cycling tech. Roka, Rapha and Le Col etc for cycling clothing and accessories.
Bike brands in particular only sell the bike frame or completed bikes. meaning parts from SRAM, Shimano, Mavic, Maxxis etc etc so there are few worth investing in directly unless their business model is just that great.
it stands to reason that the best opportunities in the cycling industry are to find promising new brands that are on the stockmarket to invest in while they are working on releasing a hot new piece of tech rather than just going to the largest most common name.
halfords is a pretty terrible option considering they are constantly offloading their cycling facilities and services to “better serve their automotive customers”. as it is halfords, cycle republic, tredz all owned by the same group but no cohesive identity to leverage in the market.