I also did a lot of research on this subject - the idea was to first start a proper professional workshop with qualified mechanics and all the tooling required. Then grow into component retail, used bikes and finally getting a few bike brands on the floor.
1st problem - Component importers are not interested in even talking to you unless you have a proper shop, and even then, they will not guarantee they will supply you and certainly not on credit for the first 12 months. So go crunch the numbers - get a shop, kit it out, tool it up, employ 2 mechanics & load your budget for TorqZone academy training, and this is only the workshop side i'm talking about.
So now you spent the money and still hemorrhaging cash on overheads without much shop income, you be buying spares and components from other retailers to do repairs - the only income you really have is labor. So you approach the importers again, and they prepared to talk mmmmmmm we see you are too close to one of our other long standing customers, sorry we not prepared to supply you even on COD basis, or yes sure no problem but then load the wholesale prices and you find you are always the most expensive.
Lets not even go down the rabbit hole of becoming a retailer for known brand of bike. 2 of the biggest brands are concept stores, so they off the table - The others will also look at your location in relation to their other big retailers and soon they will be off the table as well - So unless you planning on a shop in the middle of the Karoo in Kakamaaz you against a brick wall and a hard place.
From my research i came to the conclusion that dealing with most (not all but most) of the bike and component wholesale market is who you know not what you know.
After 5 months of business model building, planning, budgeting, phone calls, meetings etc etc - I invested my time and money in learning share & Crypto trading - Trust me, i'm a lot happier today and get far better return on investment than most bicycle shop owners.