Return None – scraping p by Python

What happens?

With string you can search for strings instead of tags, but in the way you do it looks for exact match.

How to fix?

You can go with string=re.compile() but this would be only second best solution.

Better one would be to adjust your css selector to get all the itemprop attributes:

soup.select('#js-search-product-items [itemprop="itemListElement"]')

Example

...
data_insight = []

for n in range(1):
    pages_url = f"https://www.insight.com/en_US/search.html?qtype=all&q=tp-link&qsrc=k&pq=%7B%22pageSize%22%3A100%2C%22currentPage%22%3A{n+1}%2C%22shownFlag%22%3Afalse%2C%22priceRangeLower%22%3Anull%2C%22priceRangeUpper%22%3Anull%2C%22cmtStandards%22%3Atrue%2C%22categoryId%22%3Anull%2C%22setType%22%3Anull%2C%22setId%22%3Anull%2C%22shared%22%3Anull%2C%22groupId%22%3Anull%2C%22cmtCustomerNumber%22%3Anull%2C%22groupName%22%3Anull%2C%22fromLicense%22%3Atrue%2C%22licenseContractIds%22%3Anull%2C%22assortmentIds%22%3Anull%2C%22controller%22%3Anull%2C%22fromcs%22%3Afalse%2C%22searchTerms%22%3A%7B%22TP-LINK%2520TECHNOLOGY%22%3A%7B%22field%22%3A%22field%22%2C%22value%22%3A%22A-HYBRIS-ManufacturerId~0007045098%22%7D%7D%2C%22sortBy%22%3A%22BestMatch%22%7D"
    driver.get(pages_url)
    WebDriverWait(driver, 10).until(EC.presence_of_element_located((By.CSS_SELECTOR, '[class="prod-section-container"]')))
    html = driver.page_source
    soup = Soup(html)
    soup

    for item in soup.select('#js-search-product-items [itemprop="itemListElement"]'):

        data_insight.append({
            'title' : item.find(attrs={'itemprop':'name'}).text,
            'sku' : item.find(attrs={'itemprop':'sku'}).text,
            'link' : item.find(attrs={'itemprop':'url'}).text,
            'price' : item.find("span", class_="c-currency__value").text,
            'stock' : item.find("p", class_="prod-stock").get_text(strip=True).split(' ')[0]
        })

df_insight = pd.DataFrame(data_insight)
df_insight.drop_duplicates()
df_insight

Output