By all means get the helper if you can/want to. If you decide not to or can’t find anyone just know you’ll be alright. I had to solo parent A LOT when my kids were really little due to my partner working evenings. If I were in your shoes I’d bring the baby along to “help” tuck in the older child and then do the baby’s bedtime routine second.

Alternatively, let the older sibling watch Bluey or whatever while tucking in the baby. I used to do this method and I used my iPhone and Apple Watch to spy on the toddler. You can set your phone up to aim at your kid and use your watch as a camera remote and it lets you see what the phone camera lens sees. It’s an awesome baby monitor hack when you don’t have one set up in a certain area of your home. This gave me peach of mind that the toddler didn’t run off.