I have placed my entire amateur equipment in this very inexpensive backpack:
EOS 60D with 35-70mm, 18-135mm, 70-300mm, flash, charger, monopod, tripod, lens hoods (2p.), Various filters, manuals, ...
Space for a small laptop would theoretically also. what more do you want?
To protect against rain I can not tell, but I recommend an additional rain cover, available for a maximum of 5 also here at Amazon. Then nothing can really happen!
CONCLUSION: buy recommendation for those who need a low-cost helpers. For professionals probably unsuitable for full-format cameras of the space might be too low. (Attention, only my guess!)