Tuya-Convert might not be possible for this device since the template was added (2020-02-03).
Use http://ota.tasmota.com/tasmota/release/tasmota-ir.bin firmware
WARNING The most recent versions of these devices cannot be flashed with Tuya-Convert at present. Devices with D/C 2120 and 3820 printed on the base have been unsuccessful.
Guide to opening and flashing the BW-RC1 via serial: https://www.marrold.co.uk/2020/06/flashing-blitzwolf-bw-rc1-with-tasmota.html Alternatively: http://hazymat.co.uk/2020/08/flashing-the-blitzwolf-bw-rc1-infrared-blaster-with-tasmota/ which details the use of 5v TTL adapter.