Solids does not make a baby sleep more or better.
For the 1st year of life, breastmilk or Formula is a baby's PRIMARY source of nutrition. Solids, is NOT as nutritionally dense... as breastmilk or Formula.
For the 1st year of life, a baby needs to be nursed/given his Formula, on demand. Solids, does not replace, these feedings.
At a growth-spurt, a baby naturally needs more intake and more often.
If intake is NOT keeping up WITH baby, they will always be hungry.
Nursing/feeding baby Formula, is 24/7 day and night. Their hunger/tummies do not just turn off, because they are sleeping at night.
When nursing... always do it BEFORE giving solids. Because, if you nurse after solids, baby will not be hungry... and then it will affect your breastmilk production.
This is all per our Pediatrician.
My kids as babies, had HUGE HUGE appetites. I nursed exclusively and they grew like weeds and were satisfied.
Per naps, both my kids napped ever since they were born.
You need to know, your baby's cues for tiredness.
And, if/when a baby is over-tired or overly stimulated, it makes it harder for them to get sleep and quality sleep.
I KNEW my kids cues. And they would nap. But, they would not nap, if on the go or in the car or in a stroller. They would ONLY nap, if at home in their crib. So, at nap times, I was home. And they napped. Their naps was for about 1-2 hours for my daughter. And for my son he'd nap at least 2 hours.
Also, my daughter was very sensitive to sounds. If a toilet flushed down the hall, it would wake her. I knew that.
Or, your baby is teething. As well.
Introducing solids, for the 1st year... is ONLY an introduction to foods. It is NOT their main meal nor their main source of nutrition. It is only to get them acquainted, with food. AND at 6 months, per our Pediatrician, we did not give solids 3 times a day, like an adult would eat. It was only once a day. And nursing was the main, intake.
I nursed my kids as babies, before any naps and after naps. And at night... when they woke due to hunger. I knew, when they woke or cried due to hunger. I nursed then. And I knew when they were needing more intake per growth spurts.