You need to collect CBAM data for suppliers if the total value of CBAM goods in a single shipment is 150 EUR or more.
You're wondering whether small suppliers (e.g., those with a total spend of less than 10,000 EUR) need to be included in the list of suppliers from whom you need to extract CBAM data.
According to PWC's article The EU Carbon Border Adjustment Mechanism (CBAM): Implications for supply chains
"The CBAM applies on all in-scope imports, where the shipment value is equal to or greater than EUR 150 (which is also the EU customs declaration threshold). The low value de minimis means many organisations will fall under the scope of CBAM upon the first importation of an in-scope good."
In simpler terms, this means you will likely need to collect CBAM data if the total value of CBAM goods in a single consignment (from a single supplier in any shipment) is 150 EUR or more. If the value is below 150 EUR, the regulation does not apply.