I am planning to sleep baby in a safe cot from birth day and night. I wanted advice on products such as the Dock a Tot as a portable space for baby to rest in other areas of the home (always in my supervision). I am aware that babies should lay flat on a supportive mattress. Does this type of product for this purpose only pose any safety risks? Thanks

There are a lot of portable sleep spaces on the market, which do not meet the Safe Sleep guidelines.
There are a number of safety concerns about pods & nests depending on how they are used.
These include soft, padded sides & soft base & minimal height on sides
Product Safety recommends sides of a bassinet should be 300mm high
https://www.productsafety.gov.au/products/babies-kids/kids-furniture/bassinettes

Red Nose recommends to avoid using anything soft or padded in baby’s sleep environment.
The product you mention, & most of the others have soft padded (cushioned) sides.(similar to a cot bumper)
Soft bedding is dangerous in a cot and should not be used. Soft bedding includes pillows, quilts, doonas, soft toys and bumpers. Soft bedding may cover the baby’s face and obstruct breathing and/or cause overheating.
https://rednose.com.au/article/at-what-age-can-i-introduce-cot-bumpers-and-pillows

Lullaby Trust, our colleagues in UK, provide the following information about pods & nests:
Pods/nests Pods or nests are a softer type of sleep surface sometimes used instead of or in addition to a mattress, with areas that are raised or cushioned.
When sleeping, babies shouldn’t lie on or have anything soft around them, particularly their heads, as this can cause them to overheat and increases the risk of SIDS.
Soft, squishy materials can also cover baby’s mouth and nose if they are pressed against it.
https://www.lullabytrust.org.uk/wp-content/uploads/Product-Guide-a-guide-to-buying-safer-sleep-essentials.pdf

Red Nose also has the following information about “sleep products” in general.
Not all products designed for babies are safe. They often attract parents with the promise of making sleeping, teething or carrying easier. But without safety regulations or proper use guidelines, they could cause a serious incident.
https://rednose.org.au/article/baby-products-you-dont-need